Tomcat is down or refused connection

[Ballarpure, Akshay (EXT-Tata Consultancy Ser - IN/Hyderabad)]

Hello,
Soap request is failing with below message in our application.

2014/05/20 06:48:43 [ERROR]       (browse_csl)           failed to reach 
startSearch service, soapRC 502
2014/05/20 06:48:43 [ERROR]       (soap)                Error 502 fault: 
SOAP-ENV:Server [no subcode]

I am seeing below messages in Apache's Mod JK log file.

[Tue May 20 06:48:43 2014] [57070:140373099702016] [error] 
ajp_get_reply::jk_ajp_common.c (2126): (worker1) Tomcat is down or refused 
connection. No response has been sent to the client (yet)
[Tue May 20 06:48:43 2014] [56884:140373020112640] [error] 
ajp_service::jk_ajp_common.c (2643): (worker1) connecting to tomcat failed.

Could you please check and let me know the reason for the above ?

Thanks,
Akshay